The networking industry is rapidly converting to providing packet based services like Voice over Internet Protocol (VoIP), live video, streaming, video, streaming audio, and other real-time service where a time delay between transmission and reception of data is very short and received packets arrive in the same order as transmitted packets. VoIP telephone services are rapidly expanding worldwide and threatening traditional telephone services. VoIP service provides call quality similar to conventional telephone service, but generally at much lower cost. Some VoIP telephones may be implemented as downloadable software executing on a general-purpose laptop computer, desktop computer, smart phone, or tablet computer equipped with a microphone and speakers or a headphone connector. Other configurations may allow ordinary telephones to be plugged in with a standard RJ-11 modular jack to a broadband router equipped with VoIP ports. Businesses may configure virtual PBX networks in which some of the subscriber telephone extensions are located off-site, for example at an employee's home, with data communications conducted through a broadband router.
Global communication network operators, located at a few centralized network management centers, may rely on automated network management applications to analyze, process, display and manage their networks. Network management applications may be designed to monitor network utilization and errors at regular intervals, for example at five-minute intervals, so overall network health can be determined and operational adjustments or equipment repairs or replacements made as needed. Network management applications may further provide historical data relating to a network's operation, possibly showing performance trends useful for decision making regarding utilization of network resources.
In general, VoIP calls occur asynchronously to network monitoring activities. Calls may be made at any time and may last for any duration. After a call is completed, a VoIP telephone may provide statistics relating transmission and reception of data packets carrying call data, for example average latency, average packet loss, and average jitter measurements. However, a VoIP telephone may have limited processor and/or memory resources that prevent or restrict statistics from being measured, stored, and reported.
Measurements of quality of service by a VoIP-enabled device on a communications network may differ substantially from a person's perception of quality of service. For example, if a VoIP call lasts 30 minutes, and call quality by the caller's perception is good for 29 minutes and 30 seconds, but 30 seconds of the call is perceived as very poor quality, then the caller may have the opinion that the quality of service was “very bad” or “unacceptable”. The caller's perception may differ from statistics measured by the VoIP-enabled device. In contrast to the caller's perception, the VoIP-enabled device may report a high quality of service value derived from average performance over the total time duration of the call, since the call quality was good for more than 98% of the 30-minute call duration. Statistical results including averaging calculations may not indicate when quality of service is poor according to user perceptions.